Solar cells and solar modules convert sunlight into electricity. These devices are traditionally mounted outdoors on rooftops or in wide-open spaces where they can maximize their exposure to sunlight. Unfortunately, this type of outdoor placement also subjects the solar cells and solar cell modules to substantially constant weather and moisture exposure. Due to this constant and extended exposure to the elements, solar cells and solar cell modules are preferably designed to have sufficient environmental protection to provide many years of stable and reliable operation without failure due to moisture damage or other exposure related damage. Even small solar cells for use with consumer electronic devices should have rugged environmental protection as these devices are by their nature also generally used outdoors or in areas of sun exposure where they can maximize their electric generating ability.
A central challenge in finding suitable encapsulating material for use with solar cells is finding one material that has best-in-class qualities for the many properties desired in a good environmental encapsulant. There may be some materials that provide good moisture barrier qualities but are not sufficiently transparent to pass light down to the absorber layer in the solar cell. Other layers may be good at moisture and transparent, but discolor over time and reduces transparency with ongoing use.
Traditional solar cell modules address the weatherproofing issue by using a glass sheet of sufficient size to cover all the cells in a solar module. Although glass provides a very durable and weather resistant layer, it does so at the cost of being expensive, heavy, and rigid. Glass modules are also generally more challenging to manufacture in a high-throughput manner. The use of glass also typically involves using some type of edge tape to prevent moisture from entering laterally. This further complicates the manufacturing process as it is difficult to avoid gaps in the barrier, especially at the interfaces of the edge tape and the glass as well as the edge tape and any bottom layer.
Furthermore, thin-film solar cells are more sensitive to moisture exposure than traditional silicon based solar cells. It is generally undesirable to expose any type of solar cell to direct moisture contact. This is even more true for thin-film solar cells. Hence, it is important that weatherproofing and moisture protection for thin-film solar cells equal or exceed those levels provided to silicon based cells.
Due to the aforementioned issues, improved environmental protection configurations are desired for solar cells, solar cell modules, and/or similar photovoltaic devices.